Spray nozzle



Patented June 6, 1939 marmo s'ra'res SPRAY NOZZLE Clifford H. Carr, Kansas City, Mo.

Application June 11,

3 Claims.

j My invention relates to aliquid spray nozzle and particularly to such a spray nozzle for distributing a source of water into a cone shaped spray of very ne droplets. Such nozzles are 5 particularly adapted for use in cooling ponds, for washing or humidifying air, and the like.

One of the major objects of my invention is to provide an improved spray nozzle having greater efficiency than devices heretofore developed.

Another object is to provide a spray nozzle in which a maximum of the pressure head is converted into kinetic energy of rotation whereby the water is distributed substantially entirely by the centrifugal force of the whirling water.

More specific objects are to provide a spray nozzle in which the relation between the inlet, the whirl chamber and the outlet of the whirl chamber is adapted to produce a very fine, even spray oi water. It is further objects to provide 20 such a nozzle in which the incoming water enters the whirl chamber tangent to the water in the whirl chamber; in which the entrance to the whirl chamber is between two consecutive con- Volutions of a spiral, in which the axis of the 25 inlet is symmetrical to the whirl chamber; in which the capacity of the nozzle is substantially independent of the outlet orice; and in which the relation between the inlet, the whirl chamber and outlet oriiice is such that the distance 30 between the edge of the outlet orice and the inner edge of the whirl chamber wall is substantially equal to one-half of the width of the inlet to the whirl chamber.

Other and further objects and advantages of 35 the invention will become apparent from the following description taken in connection with the accompanying drawing in which;

Figure I is a plan view of a nozzle made in accordance with the presentA invention;

Figure II is an end view of Figure I;

Figure III is a partial sectional plan View of Figure I;

Figure IV is a sectional view taken on line IV--IV of Figure I looking in the direction of the arrows;

Figure V is a sectional View taken on line V-V of Figure I and looking in the direction of the arrows;

Figure VI is an end sectional View similar to u Figure IV of a modication of the invention;

Figure vVII is an end sectional View, similar to Figure IV of a further modification of the invention; and

Figure VIII is ay diagrammatic view Showing 1936, Serial No. 84,715

the mannerin which the wall of the whirl chamber is determined.

rIhe present invention relates to that type oi nozzles in which a whirl chamber is provided into which an inlet is connected, the whirl chamber? having an outlet orifice whose axis is substantially at right angles to the inlet. Such a nozzle is usually arranged with the outlet orifice up and due to the whirlingr mo water is discharged more or less in the shape of an inverted cone.

Heretofore, spray nozzles of the type of this invention have not been entirely satisfactory because of the uneven distribution oi the water over v an area, the center of which is the outlet orifice oi the nozzle.l Nozzles of the present type are usually arranged in large groups and adjacent one another in order to utilize available space and yet operate most efciently. It is desirable -for some of these nozzles to operate with a small included angle between the sides of the conical shaped spray while others must operate with a much greater included angle. These nozzles must be capable of so operating simultaneously from a common source oipressure. Heretoiore, some of these nozzles designed to operate at a certain pressure would not operate eiciently at other pressure, nor would the included angle of spray be the same for these different pressures tion 'of the water the v because these prior devices relied almost entirely 3 upon the inlet pressure for atomization since the outlet orifice was usually smaller than the inlet. In all such devices velocity head is produced to a greater extent by the vertical component due to pressure coming directly from the inlet than by the horizontal component due to whirling movement of the water in the whirl chamber. In such prior devices this horizontal component due to whirling movement acted chieiiy to spread the sides oi the stream issuing from the outlet oriiice and depended mostly upon the velocity at the outlet orice for atomization. In all such devices the evenness ci the distribution of the nozzle is greatly affected by the size of the inlet to the whirl chamber and the size of the area of the conical spray as well as the degree of atomization, is greatly eiiected by variations in the inlet pressure.

The present invention contemplates broadly a spray nozzle in which the outlet orifice is at least as large as the inlet to whirl chamber, and much larger in sorne instances, and in which the conversion of pressure head to velocityhead is eifected at the entrance or gradually converging throat to the whirl chamber and the fast whirling water in the whirl chamber is, so to speak, squeezed out under centrifugal force through the outlet oriiice, the axis of which is at right angles to the plane of whirl chamber. Two sides of the entrance to the whirl chamber are defined by two consecutive convolutions of a spiral and the other extremities are determined by the width of the whirl chamber, which is less than the width of the source of pressure fluid.

Referring more particularly to the drawing, the spray nozzle i is adapted to be coupled to a suitable source of iiuid under pressure by means of an internally screw-threaded coupling 2 which forms the inlet. The shape of the opening changes from a round cross section to merge into a Whirl chamber 3, which has an outlet orifice i in one side of the whirl chamber; the axis of said orifice being at right angles to the plane of said whirl chamber. The outer wall of the whirl chamber is in the form of a spiral, the center of which is coincident with the axis of the outlet orice t, designated at A. The inlet to the whirl chamber is between two consecutive convolutions of this spiral wall and therefore the inlet has its throat at the point B. seen that by this construction the velocity of the incoming water increases from the inlet coupling 2 to the throat B where the velocity is a maximum due to the gradually diminishing cross sectional arca between these points. From point B on the velocity of the uid is substantially constant because of the constant cross sectional area. v

From an inspection of understood that after Figure III it will be the fluid leaves the point B three sides, by the spiral wall 5 and the lateral sides of the whirl chamber, but since the water which has passed to throat B has acquired a substantial acceleration toward the center A of the spiral, it is effectively held against the outer wall by centrifugal force. This centrifugal force has a tendency to squeeze the water against the spiral wall so that the water is forced upwardly along the upper side wall l of the whirl chamber and out the orifice 4. The apparent action of the fluid is to follow the spiral wall to the end at point B and then join the incoming stream` substantially tangent thereto so that the incoming stream eectively forms The centrifugal force of the fast whirling iiuid in the whirl chamber causes a thin iilm oi water to be forced up the sides of the outlet orice and discharge in a nely atomized cone-shaped spray.

The size of the outlet orifice and its relation to the whirl chamber and the inlet thereto is such that the distance C is approximately equal to one-half of the Width of the throat B. This allows a large portion of the water to travel a complete revolution in the whirl chamber and thus overcome any uneven flow which might be caused by the entering stream of water. By this construction the axial extent of the outlet oriiice can be reduced to a minimum and yet obtain a -very even distribution while eliminating the usual friction losses which necessarily accompany an extended orifice or high whirl chamber.

In Figure VIII, the manner of laying out the preferred curve for the whirl chamber wall 5 is illustrated. A square 9 is constructed with its center coinciding with the axis of the curve at ill. The sides of the square are equal to onefourth of the pitch of the curve 5. Then using the corners of the square il as centers an arc is ranged with respect to the struck from the extension of one side to the extension of the next side. Thus using point I4 as a center, an arc is struck from point I2 to I3; using i6 as a center, an are is struck from i3 to l5; using E8 as a center, an arc is struck from l5 to il; and using ll as a center, an arc is struck from il to I9. It will be seen that the distance between the points l2 and iii is equal to the pitch of the curve, which determines the depth of the throat B. I have discovered that such a curve produces a very efficient nozzle.

By extending the spiral wall of the whirl chamber to form the throat of the inlet B, the whirling water is tangent to the incoming stream so that the area of the throat B can be made small to get a very high velocity in the whirl chamber. By acquiring a very high whirling velocity, and by having the incoming stream tangent to the whirling water a very even and efficient atomization of the water is eifected. The termination of the spiral wall 5 at the throat B also prevents the incoming water from passing directly from the inlet'to the outlet orice with the result that the predomnating force acting on the outlet oriiice is the centrifugal force acting on the whirling water and tending to squeeze the water out against the walls of the outlet orice. The point of termination of the spiral re-entrant wall 5 is such that the inlet has curved approximately 45 degrees beyond the axis of the outlet orifice.

It is to be understood that in all of the nozzles made in accordance with the present invention, that the inlet throat to the whirl chamber determines the capacity of the nozzle, the outlet orice being of such a size that only a thin lm of water is discharged, as distinguished from a solid stream. It is necessary to keep the discharge to a thin nlm in order to get proper atomization of the water. this invention contemplates a series of nozzles in which inlet throat B is approximately of the same cross sectional area as that of the outlet orice Il for the smallest size up to those in which the cross sectional area of the throat B is substantially one-third that of the outlet orifice. In the smallest size, where throat B and the outlet orice i are of substantially the same area, the reaction of the whirling water against the incoming stream is sufficient to prevent sufcient water to ilow into the whirl chamber to completely fill the outlet orince whereby the atomizati-on of the water would be decreased. From the foregoing it will be seen that the capacity of the nozzle is controlled by the size of the inlet throat B. The size of the included angle of the conical spray can be controlled by changing the size of the outlet orice without affecting the capacity of the nozzle.

The area of the throat B is substantially twenty-four per cent of the area of the inlet at the connection 2 so that there is ample velocity increase before the water enters the whirl chamber. The whirl chamber axis of the inlet in order that no distortion of the spray will be caused thereby.

In this specication and the accompanying claims, the word atomization is used to denote a mere breaking up of a larger body of iiuid into smaller droplets and is not intended to embrace molecular disintegration.

Although water is referred to in the description, it is to be understood that it is meant to cover any like liquid that would be acted upon by It is to be understood that 40 the nozzle in the same manner as that described.

It is to be understood that various modifications and changes may be made in the apparatus described without departing from the spirit of the invention and, therefore, the foregoing description is intended as illustrative and is not to be construed as a limitation of the invention thereto.

Having described my invention, I claim:

1. A spray nozzle of the type described, comprising a whirl chamber having an outer wall in the form of a re-entrant curve and parallel end walls, an inlet passage merging into said chamber substantially tangent to said outer wall, the axis of said inlet being substantially parallel to the planes of said end walls and the distance between said end walls being at least no greater than the width of the throat of said inlet and substantially less than the mouth of said inlet, the area of the passage formed b y the re-entrant outer wall and said side walls being continuously diminished from the mouth of said inlet to the throat of said inlet, and an outlet orifice in one of said end Walls, the axis of which is disposed transversely of said inlet and between the mouth and throat thereof.

2. A spray nozzle of the type described, comprising a whirl chamber having an outer wall in the form of a re-entrant curve and parallel end walls, an inlet passage merging into said cham- Iber substantially tangent to said outer Wall, the axis of said inlet being substantially parallel to the planes of said end walls and the distance between said end walls being at least no greater than the width of the throat of said inlet and substantially less than the mouth of said inlet, the area of the passage formed by the re-entrant outer wall and said side walls being continuously diminished from the mouth of said inlet to the throat of said inlet, and an outlet orifice in one of said end walls, the axis of which is disposed transversely of said inlet and between the mouth and throat thereof, the area of said outlet orifice being at least as great as the area of said throat.

3. A spray nozzle of the type described, comprising a whirl chamber having an outer Wall in the form of a re-entrant curve and parallel end walls, an inlet passage merging into said chamber substantially tangent to said outer wall, the axis of said inlet being substantially parallel to the planes of said end walls and the distance between said end walls being at least no greater than the width of the throat of said inlet and substantially less than the mouth of said inlet, the area of the passage formed by the re-entrant outer wall and said sidey wallsbeing continuously diminished from the mouth of said inlet to the throat of said inlet, and an outlet orifice in one of said end walls, so constructed and arranged that a line passing through the axis thereof and the end of said throat makes an angle of approximately 45 degrees with respect to the axis of the inlet, the area of said outlet orice being at least as great as the area of said throat.

CLIFFORD H. CARR. 

